On Tue, Nov 10, 2015 at 04:26:02PM -0800, Shi, Yang wrote: > On 11/10/2015 4:08 PM, Eric Dumazet wrote: > >On Tue, 2015-11-10 at 14:41 -0800, Yang Shi wrote: > >>aarch64 doesn't have native support for XADD instruction, implement it by > >>the below instruction sequence: > >> > >>Load (dst + off) to a register > >>Add src to it > >>Store it back to (dst + off) > > > >Not really what is needed ? > > > >See this BPF_XADD as an atomic_add() equivalent. > > I see. Thanks. The documentation doesn't say too much about "exclusive" add. > If so it should need load-acquire/store-release.
I think doc is clear enough, but it can always be improved. Pls suggest a patch. It's quite hard to write a test for atomicity in test_bpf framework, so code review is the key. Eric, thanks for catching it! -- To unsubscribe from this list: send the line "unsubscribe netdev" in the body of a message to majord...@vger.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html
